About

Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of cancer therapeutics company AVEO Pharmaceuticals absolutely imploded, losing as much as 57% - and dropping as much as 70% for the week at one point - after its metastatic renal cancer carcinoma drug, Tivozanib, failed to win the backing of the Food and Drug Administrations' panel.

So what: In midday trading, AVEO and development partner Astellas Pharma reported that the FDA panel had voted 13-1 that Tivozanib had not demonstrated a favorable benefit-to-risk evaluation in treating advanced kidney cancer. AVEO's CEO, Tuan Ha-Ngoc, noted his discouragement with the FDA panels' findings, but plans to work closely with the FDA to improve upon what it felt Tivozanib lacked. If you recall, Tivozanib demonstrated a statistically significant progression-free survival benefit over Onyx Pharmaceuticals and Bayer's Nexavar in trials, but fell short of Nexavar in terms of median overall survival, which perplexed many.

Now what: Although the Food and Drug Administration isn't required to follow the recommendation of its panel, I'd find it difficult for them to approve Tivozanib here. I'm not saying the drug is a complete loss, as it clearly showed a benefit in PFS. However, there doesn't seem to be any way around the idea of AVEO having to run another costly trial to confirm that the median overall survival data was a fluke. Don't write Tivozanib off just yet, but I think it's time to push its development perhaps a year or two down the road.

Craving more input? Start by adding AVEO Pharmaceuticals to your free and personalized Watchlist so you can keep up on the latest news with the company.

While you can certainly make huge gains in biotechs like AVEO, the best investing approach is to choose great companies and stick with them for the long term. The Motley Fool's free report "3 Stocks That Will Help You Retire Rich" names stocks that could help you build long-term wealth and retire well, along with some winning wealth-building strategies that every investor should be aware of. Click here now to keep reading.